Reporting index management

I can see a lot of report indices that creates several shards. The reason is that I have several kibana indices, and I need as many reporting indices. It increases the number of shards I have, and I am chasing them to reduce the count

How can I customize it? I'd like to use rollover indices instead of per week indices (https://www.elastic.co/guide/en/kibana/current/reporting-settings-kb.html#reporting-advanced-settings)

.reporting-2019.10.20                                  1
.reporting-2019.10.20                                  1
.reporting-2020.02.16                                  1
.reporting-2020.02.16                                  1
...
.reporting-metrics-2018.12.09                          1
.reporting-metrics-2018.12.09